


Lab "Accident"

by SpyroForLife



Category: Invader Zim
Genre: Aphrodisiacs, Daddy Kink, Desk Sex, Dirty Talk, Established Relationship, For Science!, Grinding, Kissing, M/M, Marathon Sex, Multiple Orgasms, Neck Kissing, Office Sex, Oral Sex, Praise Kink, Rough Sex
Language: English
Status: Completed
Published: 2019-08-15
Updated: 2019-08-15
Packaged: 2020-09-01 02:31:26
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,497
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20250712
Author URL: https://archiveofourown.org/users/SpyroForLife/pseuds/SpyroForLife
Summary: Due to an accident in the pharmaceutical section of Professor Membrane's lab, Membrane, Zim, and a whole crowd of scientists get exposed to a work in progress medicine intended to be a marital aid with complete reliability and none of the usual side effects. As it turns out, the medicine does its job a little too well when inhaled rather than ingested. Luckily, Membrane and Zim are more than happy to help each other take care of their reactions to it.





	Lab "Accident"

**Author's Note:**

> ¯\\_(ツ)_/¯ Working on a proper Zim/Membrane story but basically, Zim starts working at Membrane Labs after finishing high school and ends up in a relationship with the man himself and they're really affectionate with each other and I just wanted to write smut okay. This will be canon to that fic, when I eventually post it. Anyway, enjoy this. Thing.
> 
> P.S. Zim's contributions to Science!! make him about as popular as Membrane and he is open about being an alien in public now because no one is gonna touch him. Except Membrane. He's gonna touch him all over.

One of Membrane’s last stops for the day was in the pharmaceutical section of the lab, where his employees were working on everything from an over the counter cancer prevention to multivitamins to marital aids.

The last one was more of a personal project for a particular scientist who seemed quite invested in its success.

“I’ve made a lot of progress,” the man assured Membrane, who was looking over his notes with an amused, though unseen, smirk.

Zim, who was shadowing Membrane on his rounds today due to being between projects in his own section, laughed. “So, it’s a drug to make couples more eager to sleep together?”

“In a sense. It takes that natural sex drive and just amps it up! I see it being useful for both people who suffer a low or nonexistent libido, and people who just want more energy to spice things up. There’s similar products on the market already but I wanted to try my hand at making something more reliable with less side effects.”

“I see! Well, this will certainly be popular if you get it right.” Membrane gave the notes back. “Keep up the good work, Dr. Bates.”

“Thank you, sir! I’m actually making a batch right now to test, so far it’s a liquid but I’m sure I’ll be able to refine it into capsules for easier consumption. Because as it is, it doesn’t taste very good.” Bates turned to a machine on his desk, pouring some different products into it and clicking a button.

There was a hum, and whirring as it began mixing the ingredients. Membrane stayed to watch, Zim curiously moving closer as well.

A few nearby scientists glanced over but most remained focus on their own work.

After a few moments the whirring grew louder and more strained. Bates frowned. “Uh, it’s not supposed to sound like that. Sorry, I made this machine myself and it’s a little prone to overheating…”

“You should work on it more once it’s done,” Membrane advised. “You don’t want it to blow up or something.”

“Of course. Luckily, I’ve had no problems with it so far beyond the noise-”

And then the machine blew up.

Everyone let out alarmed yelps and dove for cover, and a hot pink liquid was strewn all over the room from the device, mixing with the smoke and filling the air. Everyone luckily had some sort of eye protection on per lab safety rules, but Membrane, Zim, and Bates all got a few cuts on their faces from the shrapnel.

The machine sputtered off pathetically, sitting with medicine oozing out of it. Bates shakily yanked its power cord out of the socket for good measure, and turned to help Membrane up. “Sir, I am… so sorry.”

Membrane adjusted his goggles and sighed, examining the mess. “Is anyone hurt?” he called. He got negatives. “Okay, good. Bates, you have some cuts, please go clean them off and then fill out the usual lab injury form.”

“Should I help clean?” he asked nervously.

“You can take care of that when you get back. And relax, this sort of thing happens to everyone. No one’s hurt.”

“Right, just…” Bates gestured to the pink mist lingering in the air around them. “You’ve all been inhaling this, we should at least evacuate until it clears out. I haven’t gotten to fully test it, who knows how it could affect us.”

Membrane considered that, then nodded. “You’re right. Everyone, let’s go! Out to the hall and I’ll have this room aired out!”

They hastily left the area. Once in the hallway, Membrane closed the door and went to a nearby panel, accessing the ventilation controls and increasing the airflow through the room.

“Now we wait.” Membrane felt his face and brought his fingers away bloody.

Zim gave him a concerned look. “Do you need to go to the medical section?”

“No, I’m okay, it’s just a scratch,” Membrane assured him.

“That’s more than a scratch, here…” Zim licked his thumb and then wiped the blood off Membrane’s cheek, then rummaged through his pockets. “I’m sure I have a bandaid in here somewhere… ahah!” He whipped one out of an inside pocket. “I get little cuts all the time so I started carrying these around. Here we go…” He opened it and stretched it over the cut, patting it down and then placing a kiss over it.

Membrane couldn’t help but smile. “Thank you.” He looked at Bates. “Do you anticipate any effects from us inhaling your medicine?”

“Ah, well it’s not meant to be inhaled but rather ingested, so there could be respiratory distress, coughing, uh… and its intended effect of increased libido will likely occur, quicker now since it can absorb straight to the bloodstream from the lungs.”

Membrane froze, as did everyone else nearby. They exchanged glances, and Membrane quickly turned to Zim, grasping his shoulders. “You have a faster metabolism than us. How do you feel?”

Zim shifted. “I’m uh… not sure. Normal, I guess. Maybe a little warm but that’s all.”

“Well, sir, he’s an alien so his biology may not be affected like ours,” Bates commented. He turned to the crowd. “How are you all feeling?”

They gave unsure mutters, a few claiming warmth and a general tingling sensation. Some were starting to look a little flushed.

Membrane checked the panel on the wall, then opened the door to allow everyone back in.

The mist was gone, but there was still a vague scent lingering in the air. They were only a few steps inside when several of the men suddenly exclaimed in surprise, grabbing onto the wall or whatever else was nearby to support themselves.

“Are you okay-” Membrane started, before pausing and clenching his fists, taking a breath. After a few moments, he looked at Bates. “Well, sir, your medicine definitely works.”

Bates awkwardly crossed a leg over the other, blushing. “So it seems. Um, are you all…?” He glanced at the others, who gave him uncomfortable nods. He stumbled over to his desk and grabbed his notebook, jotting some information down. He looked around. “Even the women, are you… you know?”

“Yes!” several shouted back, annoyed.

Zim’s antennae trembled as he sensed the arousal from all the humans, but most potent were the pheromones of his mate standing next to him. Heat flared in his gut and he groaned.

Membrane leaned a bit on Zim as he addressed the group. “Okay. You know what, extenuating circumstance here… go home. You’ll be paid for the rest of your shifts, just please go home and… seek whatever medical care you may need.”

They didn’t have to be told twice, quickly gathering whatever they needed and hurrying out.

“I’m sorry, again!” Bates shouted as he chased after them.

Membrane gripped Zim’s shoulder as he watched them go, and once they were alone he leaned down to whisper to him, “Why don’t we go to my office and take care of ourselves?”

Zim straightened. “Uh, are you sure you don’t want to just go home?”

Membrane pulled Zim’s hips back against his, kneeling so he could grind against his backside. “Does this feel like I can wait to go home?”

Zim shivered when he felt how hard the other was. But he wasn’t giving in without a little teasing. “What, don’t have the self control to wait like twenty minutes?”

Membrane chuckled, acting casual despite how he was slowly rubbing his groin against the other. “Don’t act like you don’t want it.” He leaned in and nuzzled the base of one of Zim’s antennae. “I can smell your arousal.”

“Mmgh,” Zim grunted, trying to ignore the stirring between his legs. “I want it… at home, in your bed.”

“But don’t you love when I bend you over my desk and make you scream my name?”

Zim bit back a moan when the other slid a hand around to his front and slipped it under his coat, palming his crotch. “I… do love that a lot. But then we’d have to clean up your desk afterward…”

“Not if I have you on your back. Looking up at me, pleasure on your face as I make you take all of me, you calling out for me so sweetly...”

Zim spun around to face him, unbuttoning his lab coat and sliding it down from his shoulders. He leaned up to whisper against his lips, “Then take me, Daddy.”

Membrane grabbed his hand and pulled him from the room, and the two rushed through the lab with no care for who saw them, not stopping until they were in the privacy of Membrane’s office and the door was locked behind them. Zim had barely gotten his boots off before he was being grabbed and carried across the room, tossed onto the broad desk on his back.

Membrane uncaringly brushed the keyboard and monitors out of the way and gripped Zim’s hips, grinding against him as he leaned down and kissed his throat.

“Mm…” Zim tilted his head back, shaky fingers tugging on Membrane’s coat. The other let go of him for a moment to pull his arms out of it and let it drop, then he was sinking his fingers into Zim’s hips again, slipping his waistband down so he could rub circles against his bare skin.

“Tell me you want me,” Membrane murmured into an antenna.

Zim reached up, unhooking Membrane’s goggles and pulling them off. The other’s eyes were intense, heavy with lust. Zim uncaringly dropped the goggles and pulled his face over so he could kiss him. “I want you,” he said.

Membrane exhaled and dropped his hands, quickly unbuttoning his pants. “That medicine is… making it hard to think about anything other than how much I want to fuck you. Gh, I mean…”

Zim stared, and the other’s face grew very red. “Hey, I’m supposed to be the one who uses that kind of language! You naughty man.”

Membrane chuckled, sliding his pants and underwear down around his knees and moving in close again. “It seems my colleague’s marital aid is a little too strong. Though we did inhale it rather than ingest it.”

Zim nodded. “Right. It was pretty potent stuff… got me a lot hornier than I wanted to admit.”

“You should tell Bates how it affected you. I’m sure he wants all the notes he can get.” Membrane grasped himself, giving a few smooth strokes up and down as he looked at Zim. “Now, why don’t you just strip down for me.”

Zim smiled and slipped his coat off, along with his shirt. He tossed them to the floor, and gave the other a sultry smirk as he tugged his pants down and his eager erection rose up. He saw Membrane lick his lips. He moved to sit more fully on the desk, pulling one leg out but taking his time removing the other pant leg, posing a bit. “Mm, can’t wait to have you inside me, sir.”

Membrane’s fingers twitched, but he was patient, waiting for Zim to finally toss the pants off before pouncing on him, flattening him back against the desk and spreading his thighs apart. He sank down onto a knee, looking Zim over with a hungry gaze. “You’re such a mess,” he whispered as he saw how much lubricant had already run down the insides of Zim’s thighs. “Let me clean you up a little first.”

“Hm? Are you…” Then Zim felt the touch of the other’s lips against his sheath, nose brushing along his length, and he shuddered, gripping his hair. Membrane spread him open with a few gentle laps of the tongue, moaning at the sweet taste of his lubricant, and Zim moaned too, back arching. Membrane was passionate today, kissing his skin and taking little breaks to nuzzle his thighs before going back to his entrance, tongue ever so slightly teasing inside and making Zim squirm. He was very aware that Membrane was only holding onto him with one hand now, the other having dropped to tend to his own erection. Zim wanted him so bad.

“A-ah!” he gasped when Membrane pressed his face closer, tongue delving deeper inside and stroking across a spot that had him seeing stars. His claws pulled roughly on the other’s scalp and he heard him give a low chuckle. “Fuck, Membrane, please… take me.”

Membrane leaned back, licking his lips off and gently removing Zim’s hands from his hair. “Of course, love.” He pulled Zim into position, the head of his cock rubbing gently under his sheath. “Ready?”

Zim’s fingers briefly felt over the desk for purchase, and finding none, he instead lifted his hands to grab Membrane’s arms. “Mhm,” he replied, antennae perked with excitement.

Membrane said no more, pulling him firmly onto him. Zim’s body gave a jolt at being so smoothly and blissfully filled, and his head tilted back, eyes falling shut. Sometimes Membrane would pause to just savor him, but he didn’t today, instead moving into a hard, fast rhythm that made the desk shake.

Zim usually tried to be quiet when they did this at work, but the sudden passion tore a cry out of him, as the deep thrusts filled his body with pleasure. “Ah! T-that’s it, mm, more!”

Membrane tightened his hold on Zim’s hips, keeping him steady as he plowed him roughly against the desk. Zim wasn’t sure he remembered the other ever being this desperate. That doctor’s drug must be really getting to him. But Zim wasn’t complaining. This felt amazing, and he let his inhibitions slip, whimpering his mate’s name and wrapping his legs around his waist, eagerly riding his thick cock, wanting all of it inside him.

Membrane swore and leaned over him, one elbow coming down onto the table for support, and he kissed Zim hard.

Zim did his best to respond, but each thrust threatened to make him lose it and he couldn’t hold in his moans.

“So good,” Membrane whispered to him, using that low voice that vibrated so perfectly against Zim’s antennae. “You’re such a good boy…”

“Nn…” Zim shivered, tension twisting in his gut, he was already so close it hurt. He kept rocking to meet the other, focusing entirely on how good he felt inside him, everything else seeming to fade out.

Everything except his mate’s voice. “You feel so good, so hot… let me hear you. Tell me how much you love it.”

“I love it,” Zim managed, his voice hoarse. It took effort not to just slip into speaking irken. “You’re, a-ah… amazing.” He let go of Membrane’s arms, instead cupping his face and forcing his eyes open so he could admire him. The other met his gaze, focused and passionate, and Zim’s heart just swelled with love for him. He kissed him, and as he kissed back, he finished inside him.

The sensation and heat was enough to immediately get Zim off, and he cried out in ecstasy at the wave that swept through him. His insides squeezed firmly around the other and he came with several thick spurts that left him feeling breathless and exhausted, his thoughts gone in a haze of bliss.

Membrane held him tight throughout his orgasm, now softly moving inside him. Zim panted, and when Membrane stopped kissing him to ask him how he felt, Zim answered by pressing their lips back together. He wanted to draw this out as long as possible. He ran his tongue over the other’s lip and kissed him deeper, and felt him come again, causing another spark of pleasure.

Zim leaned back and Membrane withdrew, glancing down and blushing when he saw cum flow out with him. “Ah. Guess I’ll still need to clean the desk. Sorry.”

Zim smirked and wrapped his arms around his neck, giving him a light headbutt. “Don’t apologize. I love when you fill me with your cum, Daddy.”

Membrane pressed him back down, whispering, “Good, because I’m just going to keep giving it to you until this damn medicine wears off.”

“Ooh, still horny?” Zim asked, wiggling a bit. “You can have me… back home.”

The other took a deep breath and let go of him, stepping back and opening a drawer to search for napkins. “Okay. Let’s go home.”

Zim pushed himself up, wincing and rubbing his back as it ached. He accepted some napkins from the other and cleaned himself off the best he could, focusing mainly on the mess between his legs. He sighed as he slid his length back into its sheath, still feeling really sensitive. He couldn’t believe how strongly that drug had affected him.

They cleaned up the desk and got dressed, but both were both sweaty and noticeably unkempt as they left the office. They didn’t speak to anyone, just quickly clocking out and heading out to the parking lot. Despite typically being an avid follower of speed limits, Membrane broke several of them on the way back home, not helped by Zim’s hand drifting over his thigh and his partner making snide comments about what he wanted him to do to him.

It felt like ages before they were finally pulling into the driveway. They wasted no time getting inside and hanging up their coats near the door, then racing for the bedroom.

“Put your headphones on!” Zim yelled to Gaz as they passed her in the living room.

“Ugh, can’t wait to move out,” she muttered.

Up the stairs and through the bedroom door was the final hurdle, and then clothes were being shed and they were climbing into bed together, Zim pulling Membrane down on top of him as he made out with him, beyond pleased with finally getting to really stretch out and get comfortable with him, feel his bare skin sliding against his own, that heat and static erupting between them.

They were at each other for hours, both unable to get enough and never seeming to run out of energy. Zim was sure Membrane would pass out before actually choosing to stop, but the man’s stamina was off the charts today.

Along with the virility came an increased aggression, Zim noticed. Membrane always was confident and assertive in bed, but he was outright rough now. His grip left bruises and his kisses involved teeth, and though he would apologize and offer to tone it back, Zim would just shake his head and encourage it. He loved this treatment, it made him feel so desired and attractive. Not to mention, it just felt fucking incredible.

But finally, their sex drives petered out. Zim had the other pinned under him with his PAK wires, his claws tearing his skin as he filled him up, and his strong rhythm got him off with an especially strained groan.

It was like a switch flipped. Membrane went limp in his grip, panting harshly, and Zim’s antennae went forward to listen carefully, concerned by the rapid pace of his heart. “Are you okay?”

“Y-yes, just… are you almost done?”

Zim nodded, feeling pretty drained himself now. He let himself finish, wincing a bit at how it actually hurt a little. He pulled out, and a wave of exhaustion swept over him. He wavered over the other, and it took Membrane tugging at the PAK wires to bring Zim back to the present. He shook his head and unwound them, retracting them into his PAK. He crawled forward and then collapsed into Membrane’s open arms, and they cuddled up together, gazing into each other’s half-lidded, tired eyes.

“Shit,” Zim commented.

Membrane laughed. “Indeed. Are you done?”

“I think so. That… that was enough for me. Fuck. Do you think… it affected everyone like that?”

“It probably did. I hope they were all able to satisfy themselves.” Membrane was quiet for a bit, reflecting on the time he just spent with Zim. It overall just felt like a blur of nonstop need and pleasure, and as he looked at the other, his heart glowed with happiness at having such a dedicated, loving partner. He ran his palm slowly against Zim’s sweaty face, tracing his thumb along his sharp cheekbone, and he felt him lean into the touch.

Membrane yawned and dropped his head to the pillow. Keeping his eyes open was suddenly a chore. “I have… a lot of notes for Bates…” he said quietly.

“I think I have a letter of appreciation to write,” Zim said, resting his own head on a pillow and getting comfortable. “And a cake to bake him.”

Membrane chuckled. “Indeed… that was amazing, his product could change lives…” And then he fell asleep, and Zim gave him a light shake that did nothing to rouse him.

“Goodnight then,” Zim said with amusement. He listened to his heartbeat for a few moments to make sure it had returned to normal, which it had. Satisfied, he snuggled up and fell asleep with him. He was getting Bates’s ingredient list as soon as possible.


End file.
